Boston Computer Society - Sinclair Timex User Group Newsletter

OQOQThe Boston Computer Society

SINCLAIR-TIMEX USER GROUP NEWSLETTER

Volume 2, Issue 2 February 1983

This newsletter is produced to inform group members of the agenda and
logistics for future meetings, as well as to recap and amplify the information
provided at the last meeting. It also provides a forum for members and
interested parties to communicate what they have learned or developed relating
to Sinclair and Timex computer products.

USER GROUP MEETINGS

Date: Wednesday, February 16, 1983

Time : 7:00 p.m.

Place: Large Science Auditorium

UMass, Harbor Campus
(Directions on last page)

We are planning on reviews of a number of
different products purchased by members. Included
are ZXFORTH from Gladstone, the deluxe video
monitor interface from Random Access, and the
modem from Byte-Back Company. Mike Coughlin will
review ZXFORTH which is a version of FigFORTH. It
occupies approximately 8 K of RAM and uses very
little of the BASIC ROM. John Kemeny will review
the video monitor interface. Previously, he reported that he couldn't get the
unit to work. (We think he's learned how to solder.) He'll also go over the
features to look for when buying a monitor. Peter Nickols will tell us about
his modem. If you have additional items to review contact Sue or Cliff.

In addition, the Library Committee wants to report their progress and
solicit your suggestions. As in past meetings, we plan to break up into
groups to discuss topics of special interest following the formal
presentations. Tentatively, we will break into a Library group and a FORTH
group.

The March meeting will be held on the 16th, the third Wednesday of the
month. If you have items to discuss at the meeting or suggestions for
presentations, contact Sue or Cliff.

HIGHLIGHTS OF THE JANUARY MEETING

The highlight of the last meeting was the introduction of the TS-2000,
the Timex version of the Spectrum. Sue Mahoney , whose photo is above and who
now works for the Timex Computer Corporation in Waterbury, Connecticut, had
just returned from the Winter Consumer Electronics Show (CES) in Las Vegas,
Nevada. At the CES, Timex made the formal announcement of the TS-2000.

HIGHLIGHTS

Continued

The TS-2000 will be basically the same as the Spectrum# The Spectrum is
the successor to the Sinclair ZX-81. It sports a larger keyboard; 10 octave,
130 semi-tone sound; 8 colors; high-resolution graphics; and upper and lower
case letters. It uses the single keystroke commands like the ZX-81. And
ZX-81 software can be easily transported to the Spectrum. However, the
Spectrum uses a faster, but not compatible, cassette recording technique.

Timex does plan to do some modifications to the Spectrum. First, it must
be modified to use the National Television Systems Committee (NTSC) standard
used by U.S. television instead of the PAL system used in the United Kingdom.
Also, Timex will be creating a plug-in slot for what they are calling
solid-state software. Matchbox-size cartridges (like for the Atari game, only
much smaller) will plug into the top of the machine. The solid-state
cartridges will sell for $12.95 to $24.95, versus $9.95 to $19.95 for tape
cassettes .

Sue demonstrated a TS-2000 prototype. The unit was in a Timex case, but
did not have the cartridge interface or NTSC color. Sue brought her own PAL
television. Two models of the TS-2000 will be sold. One will have 16 K of
RAM and the other 48 K. They both will have a 16 K ROM. They will list for
$149.95 and $199.95, respectively. The announced availability is the second
quarter of 1983. Sue expects at least 20 software titles to be available when
the TS-2000 gets to the market.

Sue also demonstrated the TS-2040 printer. It is a 32-column dot matrix
thermal printer. It can use the Sinclair-Timex LPRINT, COPY, and LLIST
commands. It will list for $99.95 and was expected to be in the stores by the
end of January. It didn't make it! The printer will be compatible with the
TS-2000.

The TS-1050 Communications Interface Device (300-baud modem) has been
delayed and will not be available until the third quarter (September?). Sue
also stated that the Timex Computer Club newsletter will be out soon.

Other Sinclair-Timex related companies at the CES were Sinclair Research
(which is looking at the international marketplace), Mindware , and Softsync.

We have no reports from those companies.

Cliff Danielson spoke to the group about volunteering. He outlined
several specific jobs that need to be done. The most important outstanding
job is that of newsletter publisher. He, she, or they would be responsible
for managing newsletter advertizing. There are many organizations that would
like to pay for ads in this newsletter. This, of course, would be of benefit
to the whole group.

Cliff also asked for a librarian, and, as you can see on the back page, a
Library Committee has been formed. Other jobs include: a 'one day a month'
job to sort and mail newsletters; contributions to the newsletter (of
articles, artistic creations,...); and a program chairman to arrange for
speakers and handle logistics at our meetings.

Representatives of the Computer Advertising Network demonstrated their
service during the break. The service, which is paid for by the advertizer,
allows access via a telephone line and 300-baud modem to a wide variety of
information. For access dial 423-6300.

REVIEW OF MATRIX PLANNER by J. N. Kemeny

Matrix Planner is a spread sheet program distributed by Mindware. It
requires the 8 K ROM and 16 K RAM. The early version we got cost $45.00, but
this was before Sinclair and Timex introduced their spread sheet product,
VU-CALC, which was reviewed in the December newsletter. Matrix Planner is
very different from VU-CALC.

Firstly, Matrix Planner is written entirely in BASIC. This means you can
examine and change the program, even add new features. Comments in the
program help you understand how it works. For example, the program gives you
30 rows by 8 columns of cells, but you can change this. Formulas are entered
as strings, and are evaluated using the VAL function. This offers the
advantage of being able to use all the BASIC functions, such as SIN and PI, in
a formula. Also formulas can be any length up to 30 characters, and each cell
can have its own, different, formula.

Matrix Planner displays four columns of data at a time (see figure).

Each cell is displayed as seven characters, but the actual precision of the
stored data is the same as that of a BASIC variable (VU-CALC truncates at
eight digits).

One of the delights of VU-CALC is that moving from cell to cell is such a
smooth operation. Because it depends on INKEY$, Matrix Planner is not smooth.
Worse, in Matrix Planner, if you move the cursor off the screen, it takes
several seconds to paint a new picture. This situation is ameliorated by a
"go to" function, which takes you to a particular cell with only the delay
required to paint one new screen.

The cursor in Matrix Planner is
confusingly displayed — in the figure it is
the inverted character in cell B4. There is
an annoying bug that sometimes leaves the
inverted character after the cursor has moved
on. This is not the only bug in the early
version of the program we got. For example,
line 1350 should be GOTO 307.

But the biggest problem with Matrix
Planner is in its use of relative formulas.

There is a "replicate" function which allows
inserting a relative formula one cell to the
right of the last formula. But there is no
way (other than cell by cell) to create
relative formulas along a column! Thus, the
additional function, "sum" (which could
easily have been computed via relative
formulas) had to be included just to get the
sum of a column.

In conclusion, Matrix Planner is an
interesting first pass at writing a spread
sheet program in BASIC. In many ways it is
more powerful than VU-CALC. But if you are
looking for a practical spread sheet program,
we recommend VU-CALC over Matrix Planner.

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SAVING AND LOADING PROGRAMS

TRIAL AND ERROR?

You may find as a beginner with the Sinclair-Timex computers that you
have problems loading programs from cassette tapes. Even as an old hand, you
may frequently have problems. This article provides some suggestions and
hints .

Most problems occur when the tape recorder used to load a program is
different from the tape recorder used to save it. Once you master load and
save procedures with your tape recorder, you should have little trouble with
the tapes you record. It should not matter what tape recorder you use.

However, there may be problems with older or cheaper ones.

A very old recorder may work fine for saving and loading programs you
write, but may not be able to load commercial tapes. This turned out to be
the case for your editor's old recorder, which, due to the years of wear, was
running approximately 30 percent too slow.

Cheaper recorders can also cause problems. 'One member had three
different tape recorders each of which could load programs written by a good
recorder. But, they could not save programs properly. If you suspect tape
recorder problems, borrow one and experiment. A new recorder could solve your
problem. The portable ones are generally easier to use and normally have the
proper earphone and microphone jacks. Your editor currently has an
inexpensive ($32.00) Radio Shack Model CTR-37, and it works fine. Several
members are using the mini- and micro-cassette recorders without problems.

The choice of brand and quality of cassette tape doesn't seem to be too
critical. We have heard reports of short dropouts on high-fidelity tapes, so
perhaps its best to stick to the cheaper tapes or data-grade tapes. You can
buy C-20 tapes for under one dollar by mail order. C-20 tapes are long enough
to save two copies of most programs on a side, while still short enough to
conveniently use both sides.

Equipment layout and interconnect are perhaps more critical during tape
save and load than at any other time. You should have your computer on a wood
(nonraetal) table. All cables and peripherals should be securely connected.

The RAM pack should be taped or secured so that it doesn't "wobble" when you
press keys. Until you have reliably mastered tape save and load, you could
leave the RAM pack off. However, don't make a practice of removing it too
often or the connector will loosen, leading to other problems.

The cassette recorder should be connected to the same electrical outlet
as the computer and television, to reduce induced 60 cycle hum. Turning one
plug over in the socket can also affect 60 cycle hum. If your tape recorder
will operate from batteries, try running it on the batteries. The recorder
and computer should be positioned such that the cable connecting them does not
run under the computer or memory pack. Keep the computer, recorder, and
television separated by some distance to miminize interference. Make sure
that the connectors are clean by wiping with a clean dry cloth.

When loading a tape, the cable provided with the computer should be
connected from the ear jack on the computer to the ear jack on your recorder.
No cable should be connected to the mike socket. Connecting both the ear and
mike at the same time can cause ground loops which could interfere with
loading. For saving a tape, connect the cable from the mike socket on the

SAVING AND LOADING PROGRAMS

Continued

computer to the mike socket on your recorder. Unplug the ear jack cable.

Later you may find that you can leave both ear and mike jacks plugged in, but
initially use only one at a time. Use an ohmmeter to check that the cables
are not defective. Your problem may be just a broken wire.

Here's a short program to start with:

1 DIM A$(500)

2 SAVE "A$"

If you do not have an automatic record level feature on your recorder, set the
recording level at 3/4 full volume. If you've got a record level indicator,
do a test recording and set the level such that the needle is near its top but
still vibrates or the light is near it's full brightness but still flashes.

This should put the recorder near the top of its linear region. Again make
sure that the cables are firmly* connected . Rewind the tape and begin the
recorder. Remember to press the record button! Wait about 4 or 5 seconds to
ensure that the tape has advanced past the leader. Now RUN the program. Note
the pattern on the television. There are distinct light and dark bands and
passing spots. The pattern is not washed-out grey, nor is it heavily black.
When 0/2 appears on the screen, stop the recorder and rewind the tape.

Before you connect the cable to the ear jack of your recorder, play some
of the tape you just recorded. First, you should hear a buzzing or popping
noise, followed by a 5-second silent period. There may be a small 60 cycle
hum during the silent period, but it shouldn't be too loud. If it is, turn
the volume down. Next comes the loud high pitched buzzing of the actual data
you recorded. Adjust the volume to a level where this sound is loud, but not
distorted. This level will probably be between 1/2 and 3/4 full volume.

Rewind the tape.

If you have tone controls, set the bass to minimum and treble to maximum.
If you have a single tone control, this is usually the maximum setting. Check
that the ear jack plugs are securely in place. Now do a trial load to adjust
the volume. Type LOAD "TEST” and Newline (Enter). This won't load the tape
since the program was given the name A$. Play the recorder. After the
initial noise and silent periods, you should see a pattern on the television
which is similiar to that when you created the tape. The television sync lock
may not permit the identical pattern, but it will have the same quality of not

washed-out grey, not heavily black, but distinct light and dark bands. If you

don't see these patterns, adjust the volume control to just above the level
where the pattern first appears. Rewind the tape.

Now, if everything works right, you should be able to load the tape.

Enter LOAD "A$!l and start the recorder. You should get a return of 0/0
indicating proper load. Press Newline to see the original program. Enter
PRINT A$. You should get a screen full of blanks. If you don't get the 0/0
indication or if A$ contains nonblank data, you have a problem. Rewind the
tape and begin adjusting the load volume (probably up, a little at a time)

until you load. In loading a commercial tapes, follow the same procedure as

for your own tapes.

Very important hint — once you get a commercial tape to load, save a
copy of it with your own recorder. Unfortunately, this is not always possible
because some manufacturer's programs are designed so that they cannot be saved.

YOUR REMs

LOOSE CONNECTION: R. F. Valle of East Boston writes that it is
exasperating to lose programs because the nine volt miniature 3.5 mm power
plug connector is loose. He says the problem occurs because the tip of the
jack is considerably smaller than the sleeve. His solution is to replace the
plug with an American manufactured one (such as a Switchcraft) whose tip is
the proper diameter.

DATA STATEMENT STATEMENT: Bob Smith of Needham found a, ugh, bug
(calling it a typo won't get us off the hook) in the "Wherefore the Data
Statement" article from the November newsletter. In line 540, variable DI
should be DJ. Bob also writes that the program solution we published is
really an oversimplification. He says some BASICS use READ, DATA, and RESTORE
in more complex forms, arbitrarily combining string and numeric data.

OLD ROM ADDS UP: Gary Preston, editor of Slug , the newsletter of the
Franklin County Virginia Users Group, was the first to send in the checksum
for the old 8 K ROM for the ROM TEST program we published in the December
newsletter. He also listed the differences between the old and new ROMs:

OLD ROM

NEW ROM

Checksum = 854885

SQR .25 equals 1.359

.25 ** 2 equals 3.1423844

PEEK 54 gives 132

POKE 16437,255 required after

Checksum = 855106
Gives correct answer
Gives correct answer
PEEK 54 gives 136
PAUSE Not needed.

Thank you all for your REMs.

P-ARY "DECIMALS" 8 K ROM

Last month we introduced you to "binary decimals." Here's a short
program to convert denary (base ten) fractions to binary.

10 LET P=2
20 INPUT F

30 PRINT "THE DECIMAL FRACTION ";F-INT F,

"IN " ; P ; "-ARY IS APPROXIMATELY 0.";

40 LET F=P* ( F-INT F)

50 PRINT INT F

60 IF F>0 THEN GOTO 40

RUN the program. Enter 0.5 and note that the answer is 0.01111111
11111111111111111111111110, which is only an approximation to the correct
answer 0.1; this is due to round-off error in the floating point
representation. Enter 1/2 and you'll get the exact answer. Entering SQR 2
shows that 1.0110101 is an excellent binary approximation to the square
root of two.

If you want P-ary, instead of binary, change the value of P in line
10. Try P equal to 7. RUN the program and enter the function P_I. Be sure
to review the difference between precision and accuracy before interpreting
the results.

SINCLAIR-TIMEX RELATED BOOKS FOUND IN THE GREATER BOSTON AREA
Compiled by R. F. Valle

Baker, Toni. Mastering Machine Code On Your ZX-81.

Reston, Virginia: Reston Publishing Company, 1981.

Campbell, Siminoff, and Yates. The Timex Personal Computer
Made Simple . New York: New American Library, 1982.

Chiu and Mullish. Crunchers - 21 Simple Games for the
Timex/Sinclair 1000 2K. New York: McGraw-Hill, 1983.

Giarratano, Joseph C. Timex/ Sinclair 1000 User's Guide,
Volume 1. Indianapolis: Que Corporation, 1982.

Harrison, Mark. Byteing Deeper Into Your Timex/Sinclair
1000. New York: John Wiley and Sons , 1982.

Hartnell, Tim. Making the' Most- of Your ZX-81. Reston,
Virginia: Reston Publishing Company, 1981.

Hartnell, Tim. 49 Explosive Games for the ZX-81. Reston,
Virginia: Reston Publishing Company, 1982.

Hartnell, Tim and Jones. Mastering Your Timex Sinclair
1000 Personal Computer. New York: Bantam Books , 1983 .

Hergert, Douglas. Your Timex Sinclair 1000 and ZX-81.
Berkeley, California: Sybex, 1982.

Hurley, Randle. The Sinclair ZX-81, Programming for Real
Applications . Beaverton, Oregon: Dilithium Press, 1982.

Milgrom, Alfred. 30 Programs for the Sinclair ZX-80 IK.
Melbourne House.

Norman, Robin. ZX— 81 BASIC Book. Indianapolis, Indiana:
Howard W. Sams and Company, 1982.

Toms, Trevor. The ZX— 81 Pocket Book. Reston, Virginia:
Reston Publishing Company, 1981.

Vickers, Steven. Timex User Manual. North Attleborough,
Massachussets : The Communications Company, 1982.

QZX CQ

Qzx is a newsletter for people who have a combined interest in amateur
radio and the Sinclair— Timex computers . They are also know by the
none-too-kosher term, hamhackers. The newsletter contains a lot of good
information, especially about hardware. There are ads for systems which
encode and decode Morse code using our computer. Also, there are meetings for
hamhackers on the air. For example, a Sinclair— Timex net meets Wednesday
nights at 10 p.m. EST on the 20 meter band at about 14.345 MHz.

Subscriptions to QZX are $12 ($19 foreign). Write to Alex F. Burr, KSXY,
2025 O'Donnell Dirve , Las Cruces, New Mexico 88003.

73 (that's ham talk for ciao).

GENERAL INFORMATION

Meetings are open to the public; however, attendees are
encouraged to join the Boston Computer Society (BCS). This newsletter is free to
members. Backissues are one dollar each.

FOR MORE INFORMATION

Sue Mahoney, Director of the Sinclair-Timex User Group
c/o The Boston Computer Society or call (203) 573-5816.

Cliff Danielson, Newsletter Editor

14 Davis Road, Chelmsford, MA 01824, (617) 256-4638.

John Kemeny , Contributing Editor & Correspondent With Other User Groups
284 Great Road, Apt. D5 , Acton, MA 01720.

Library Committee: Beth Elloitt, Sean O'Bahilly, and Bob Sanchez.

DIRECTIONS TO THE MEETING

The Sinclair-Timex User Group meets in the Large Science Auditorium
(Room 8/2/009) of the University of Massachusse ts of Boston, Harbor Campus.
The Harbor Campus is only 3 miles from downtown Boston and easily
accessible by public and private transportation. From the north or west,
take the Southeast Expressway to Exit 17. Turn left onto Columbia Road.
Enter the rotary and take the first right (Morrissey Boulevard). Bear
right on the traffic island, following UMass/Boston sign. Turn left into
the Campus. From the south, take Morrissey Boulevard northward to the
campus. On the MBTA, take the Red Line (Ashmont Train) to Columbia
Station. Transfer to the free University shuttlebus in the T parking lot.

IMPORTANT NOTICE ! If the mailing label on this newsletter is handwritten
(except if your a user group) , then you are not on the mailing list of the
Sinclair-Timex User Group. You need to either join the BCS or, if you are
a BCS member, contact Mary McCann in the BCS office to be added to the
Sinclair-Timex mailing list.

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